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Eukaryotic Mechanosensitive Ion Channels
Published in Tian-Le Xu, Long-Jun Wu, Nonclassical Ion Channels in the Nervous System, 2021
Various transient receptor potential (TRP) channels are involved in mechanosensation in sensory neurons, including TRPV1, TRPC5, and TRPV4. TRPV1 has recently been implicated in controlling the stretch response of bladder urothelium, since the knock-out mice showed defects in voiding. However, no mechano-currents have been recorded from urothelial cells, suggesting that TRPV1 may detect the presence of molecules produced by stretch and may act downstream of the real MA channel [7]. TRPC5 has been shown opened by hypo‐osmolality and plays a role in baroreceptor mechanosensing [8]. However, since a hypo-osmotic stimulus contains both chemical (decreased ionic strength) and mechanical (cell swell) components, more specific mechanical activation should be taken into consideration. A recent study provides clear evidence that membrane stretch failed to activate TRPC5 in a heterologous expression system [9]. These studies suggest that both TRPV1 and TRPC5 serve the downstream of mechanosensation as MS channels.
Mechanotransduction Mechanisms of Hypertrophy and Performance with Resistance Exercise
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Andrew C. Fry, Justin X. Nicoll, Luke A. Olsen
Life on earth has evolved in the presence of a constant gravitational force, 9.8 m/s2 to be exact. Like all evolutionary selective pressures, this specific stimulus necessitated both unicellular and multicellular organisms to sense and respond to its physical environment in a concerted, functional manner. Throughout time, the human body has done just that; it has developed structures such as the otoliths in hair cells to sense gravity and maintain equilibrium; it has equipped cells with a structural framework to sense and transmit changes in cellular tension such as the cytoskeleton; and it has developed small contractile units, such as the sarcomere, as a means to overcome gravitational force and allow locomotion through muscle contraction (127). Thus, the evolution of mechanosensation and transduction is at the foundation of cellular communication. While the significance of cellular mechanotransduction is readily agreed, the mechanisms through which the cell, and more specifically the muscle cell, can respond to an external stimulus is still under intense investigation. Mechanotransduction, defined as the ability of a cell to sense and respond to a mechanical stimulus (78), can be separated into two non-exclusive pathways; specifically, biochemical and biophysical mechanotransduction.
Participation of Vagal Sensory Neurons in Putative Satiety Signals from the Upper Gastrointestinal Tract
Published in Sue Ritter, Robert C. Ritter, Charles D. Barnes, Neuroanatomy and Physiology of Abdominal Vagal Afferents, 2020
R.C. Ritter, L. Brenner, D.P. Yox
Recordings from gastric mechanoresponsive fibers in the vagus were among the first data supporting the vagal role in gastrointestinal sensation. For example several studies in the 1950s reported vagal fibers that increased their firing in response to gastric distension.36,37,58 Subsequent experiments by many groups confirm that the stomach is mechanosensitive and demonstrate the existence of mechanosensation from both the fundus/corpus and the gastric antrum (for review see Grundy and Scratchard34). It appears that both the fundic and antral mechanoreceptors are “in series,” stretch receptors, responding to increases in tension rather than muscle fiber length (for review, see Grundy, chapter 8 in this volume). However, considering the nature of discharge of antral and fundic receptors during physiological stimulation and the physiological functions of the antral and fundic gastric regions, it would appear that tonically discharging fundic receptors are likely to provide information on gastric fullness, while antral receptors telegraph the phasic activities of the antral mill to the brain. Thus, information from the fundic, capacitance, region of the stomach might be expected to be more important for the control of food intake. “In series” stretch receptors are adapted to monitor tension, regardless of its cause, rather than to monitor muscle fiber length, as is the case with parallel receptors, such as the muscle spindle. In other words, the gastric mechanoreceptors are adapted to monitor intragastric pressure.
Mechano-gated channels in C. elegans
Published in Journal of Neurogenetics, 2020
Mechano-gated channels are evolutionarily conserved mechanical gates regulating mechanosensation like touch, hearing and proprioception (Kung, 2005). Through mechanotransduction process, gated ion channels convert mechanical stimuli into electrochemical signals thereby triggering mechanosensation. When a mechanical stimulus is applied, membrane tension or force spring leads to structural deformation of the gated protein. As such, the gated channel opens in order to allow the flow of ions to generate graded receptor potentials which triggers mechanosensation (Marshall & Lumpkin, 2012). Bacterial mechanosensitive channels (MscL, MscS and MscM) in E.coli are gated by changes of membrane tension forming non-selective pores through which hydrated ions and solutes can flow, and act as osmosensors for turgor control (Rasmussen & Rasmussen, 2018). In eukaryotes, a few cation-selective channels — degenerin and epithelial sodium channels (DEG/ENaC), N-type Transient receptor potential (TRPN), two-pore potassium channels (K2P), transmembrane-like proteins (TMC) and Piezo have been classified as bona fide mechano-gated channels (Delmas & Coste, 2013; Jin, Jan, & Jan, 2020). It is still enigmatic whether any anion channel such as chlorides can characterize mechano-gated channels.
A short guide to insect oviposition: when, where and how to lay an egg
Published in Journal of Neurogenetics, 2019
Kevin M. Cury, Benjamin Prud’homme, Nicolas Gompel
Mechanosensation. There is surprisingly little literature that explores the role of mechanosensation in sensing mating and triggering post-mating responses in insects. Yet, there are reasons to think that this modality is also involved in the switch. The external genitalia of female insects are covered with mechanosensory bristles and sensillae (Snodgrass, 1935; Taylor, 1989). While these organs may play a role during the process of oviposition, they may also be stimulated during copulation (Yassin & Orgogozo, 2013). Perhaps analogous, a single pair of bristles on the genital claspers of male D. melanogaster are necessary for maintaining proper posture during copulation (Acebes, Cobb, & Ferveur, 2003). There is also circumstantial evidence that the female insect reproductive system senses mechanical stimulation, for instance in response to ovulation (Gou, Liu, Guntur, Stern, & Yang, 2014) (see below) or through copulation, resulting in removal of a previous male's sperm from the spermathecae (von Helversen & von Helversen, 1991).
The role of the facet capsular ligament in providing spinal stability
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Emily A. Bermel, Victor H. Barocas, Arin M. Ellingson
For the FCL to serve a proprioceptive role, which has been suggested by previous works (Cavanaugh et al. 2006; Zarei et al. 2017), there must be sufficiently large strains in the tissue to trigger a neuronal response. In this work, we found large stretches for loading levels in all types of bending, which may play an important physiological role – as it is known the FCL contains proprioceptive nerves (Cavanaugh 1995). Thus, the FCL has the potential to serve effectively as a proprioceptive sensor. As the mechanical integrity of the FCL diminishes, a substantial increase in FCL stretch was observed, which provides insight into the pain mechanism of spinal instability. Additionally, joint contact is an important indicator of potential pressure points on the facet surfaces caused by motions (Jaumard et al. 2011). Pressure points and joint contact could be another component of the mechanosensation of the joint with feedback for the health of the bone and cartilage of the facet joint. Further research into the degeneration of the entire joint is needed to understand how all these components are interconnected and how they affect low back pain.